1. Field of the Invention
The present invention relates to a light emitting device, particularly to an organic electroluminescent device, that can prevent corrosion of data lines and scan lines, and improve the adhesive strength of a sealant.
2. Description of the Related Art
Organic electroluminescence is a phenomenon of making an exciton by recombining an electron and a hole injected into an organic (high or low molecular) thin film through an anode and a cathode, and emitting a light having a predetermined wavelength by energy from the exciton.
An organic electroluminescent device in the art includes anode electrode layers, cathode electrode layers, scan lines, and data lines.
A plurality of pixels are formed on an emitting area crossing over the anode electrode layers and the cathode electrode layers.
The data lines each are connected to the anode electrode layers to receive data signals transmitted from an integrated circuit chip and transmit the received data signals to the anode electrode layers. The scan lines each are connected to the cathode electrode layers to transmit scan signals transmitted from the integrated circuit chip to the cathode electrode layers.
In case a positive voltage and a negative voltage are respectively applied to the anode electrode layer and the cathode electrode layer, a light having a certain wavelength is emitted from the organic layer.
The scan lines and data lines are also located on an area to which a cap for encapsulating the organic electroluminescent device is adhered. Thus, if a sealant that is an adhesive used for adhering the cap is spread on the above cap-adhering area, the sealant is placed on each of the scan lines and data lines.
FIG. 1 is a sectional view illustrating the structure of a scan line in the art.
In FIG. 1, each scan line 4A includes an ITO layer (Indium Tin Oxide layer, 4A-1) formed on a substrate 1 and a sub-electrode layer 4A-2 formed on the ITO layer 4A-1.
To lower resistance of the scan line 4A, the sub-electrode layer 4A-2 consisted of a metal having better conductivity than the ITO, for example Mo, is formed on the ITO layer 4A-1. The sub-electrode layer 4A-2 is connected to the cathode electrode layer.
Thus, in the scan line 4A shown in FIG. 1, galvanic corrosion by moisture occurs at an interface of the ITO layer 4A-1 and the sub-electrode layer 4A-2.
Galvanic corrosion is a phenomenon that a metal is corroded by forming an oxidation-deoxidation reaction through movement of an electron when there is a voltage difference between two metals (or same type of two metals) whose corrosion conditions are locally different.
The galvanic corrosion occurred in the interface of the ITO layer 4A-1 and the sub-electrode layer 4A-2 increases resistance of the scan line 4A to lower transmittance velocity of scan data to a pixel.
Also, the data line is formed in the same structure as the scan line 4A in FIG. 1.
Thus, the galvanic corrosion is occurred in the data line the same manner, and increases resistance of the data line to lower the transmittance velocity of data to the pixel, resulting in serious effect to the light emitting device.